Stocks are an entitlement to a future income stream, created by a the real business of the company being invested in. It's just that there's a lot of levels of indirection.

A lot of traders are just gambling, but there is also something of value being created.

Stocks are risky. People don't like risk. So the current price of a stock will always be less than its expected future value. Therefore the value of the stock will tend to go up.

So when you own a stock you're being paid for bearing the risk. This is a real service of value that you're providing for the world.

Most people don't look further than the stock price and if they like the company. In that case, it is gambling. People think they don't have to spend any time and they should get a good return.

Like Peter Lynch says, most people spend more time deciding on what refrigerator to buy than the stock they're buying. If you spent as much time researching a stock as you do a house, you'd probably do much better in the market.

Stop buying stocks only because someone told you to or because you like the company.

Nothing is being created. You're right, it is completely a gamble, unless you have some form of (not necessarily illegal) insider knowledge. But capitalists love the art of stock gambling because it gives the feeling that is related to something productive (a business). And they also perfected the art of extracting money from society (pension funds, retirements, sovereign funds) to fuel these stock-trading activities. So it is very lucrative for a small group, a little over inflation for many people, and a big loss for a lot of less fortunate investors. It also help concentrate business in the hand of a few, because if you have lots of money you can buy the advice of the best money managers and let the small investors bear the losses.